Circumferential main grooves are formed on a tread of a pneumatic tire in order to obtain wet performance.
It is known that a center rib pattern tire having a center rib that extends along a tire circumferential direction on the tire equatorial plane is more excellent in steering stability performance than a center group pattern tire having grooves in the circumferential direction on the tire equatorial plane.
When the width of a center rib (i.e., central land portion row) is further made larger, although steering stability of the tire is enhanced, conversely, wet performance is deteriorated.
Thus, relating to a passenger car, a light truck or the like, a tire having lateral grooves formed on a center rib is generally used in order to prevent deterioration of wet draining performance (for example, Japanese Patent Application Laid-Open (JP-A) No. 11-91315) However, when a lot of lateral grooves is used for the center rib in order to enhance wet draining performance, a problem is caused that land portion rigidity of the center rib is deteriorated thus deteriorating steering stability.
In other words, in a conventional art, it has been difficult to allow steering stability and wet performance to coexist.
In view of the aforementioned facts, an object of the present invention is to provide a pneumatic tire capable of improving wet performance without sacrificing steering stability.